Catastrophic oil spills like that of the Exxon Valdez in AlaskaPhoto: © 1990 Ken Graham/Ken Graham Agency
But, says Earle, by 1970, when Heyerdahl set out on another raft journey, this time across the Atlantic, something of a “sea change” was already underway. “He reported seeing far more oil lumps than fish, and alerted the world about the enormous quantities of trash, oily wastes and plastic debris he observed in the sea.”
Heyerdahl was a harbinger of deepening bad news for the world’s oceans. Since the 70s, commercial fisheries have pushed fish stocks to collapse. Pollution has claimed the lives of millions of seabirds, and untold numbers of birds, marine mammals and sea turtles become entangled or ensnared each year in plastic debris that finds it way into the sea. Vital coastal habitats are being buried, damaged, altered or destroyed by construction and development.
In response, the United Nations has declared 1998 the International Year of the Ocean. This year’s Expo, or World Fair, to be held in Lisbon, Portugal, will have the oceans as its main theme. And across the globe, scientists, environmentalists and others are training their focus on the array of human impacts that are making themselves felt on the global ocean:
Fisheries: Reaching Depletion
According to the United Nations Food and Agriculture Organization (FAO), an estimated 70 percent of global fish stocks are “over-exploited,” “fully exploited,” “depleted” or recovering from prior over-exploitation. By 1992, FAO had recorded 16 major fishery species whose global catch had declined by more than 50 percent over the previous three decades-and in half of these, the collapse had begun after 1974. In 1992, the virtual disappearance of Northwest Atlantic groundfish led the Canadian government to close commercial fisheries and, later, all fishing on these stocks. A 1997 paper in the British journal Nature predicted that, unless swift and effective action was taken to protect them, cod stocks in the North Sea were also in danger of collapse. At least one species-the California white abalone-is now considered a likely candidate for extinction, 20 years after intense exploitation ended.
At the same time, as much as 27 million tons of fish are thrown overboard annually because they are undersized, of the wrong species, of inferior quality or surplus to quotas. A study in Alaska suggests that Bering Sea red king crab discards amounted to 16 million animals in 1990, more than five times the number actually landed.
Large numbers of marine mammals, sea turtles and seabirds are also caught in commercial fisheries operations around the world. The National Research Council has identified bycatch in shrimp trawls as the most significant cause of sea turtle mortality in the US. Tuna long line fisheries in the Southern Ocean are estimated to entangle at least 44,000 albatrosses every year, and possibly many more. Harbor porpoises are caught in large numbers virtually everywhere gill nets are set in coastal waters.
Aquaculture, or fish farming, which is often touted as a panacea for the problems of fisheries over-exploitation, is not necessarily an answer. The construction of aquaculture facilities can result in the loss and fragmentation of habitats, particularly mangrove forests. Fish farms also often result in high levels of nutrient and chemical pollution and the escape of introduced fish species and associated diseases into the wild. In addition, large numbers of wild fish are caught to feed those raised in farms: for example, the production of one ton of cage-reared salmon requires approximately 5.3 tons of fish. The over-exploitation of stocks for fishmeal is considered the likely cause of the dramatic collapse of some seabird populations in the North Sea region during the 1980s.
Pollution: Our Global Garbage Can
Pollution of the ocean comes in many and varied forms, and from a wide range of sources. The National Research Council has estimated that as many as 8.8 million tons of oil enter the ocean each year as a result of human activity, and that at any given time, the ocean contains 280,000 tons of tar balls. All kinds of garbage, ranging from fishing nets to trash from cargo ships to litter on the beach, finds its way into coastal waters and the ocean, where it traps, ensnares and entangles marine wildlife such as marine mammals, sea turtles and seabirds. Plastic pellets have been found on the surface of the Pacific at concentrations of 21,000 per square mile; a clean-up exercise on the coast of Texas yielded 15,600 six-pack rings along 1.8 miles of coastline; and a National Academy of Sciences review once estimated that over 14 billion pounds of garbage enters the ocean from sea-based sources alone. In the 1980s, it was reckoned that 30,000 northern fur seals died each year after becoming entangled in marine debris, principally lost or abandoned fishing gear.
Heavy metals-for example, mercury and lead-and organochlorine compounds such as PCBs and DDT have been associated with a wide range of impacts on marine wildlife. According to Boyce Thorne-Miller, senior scientist with SeaWeb, a marine conservation education initiative of The Pew Charitable Trusts, “Although it’s difficult to definitively establish cause and effect in a lot of these cases, these contaminants have been linked with mortality, malformation, reduced hatching success, developmental abnormalities and chromosome aberrations in fish eggs and larvae contaminated at the surface, and reproductive problems and reduced immune system in marine mammals.” Because heavy metals and organochlorines are bioaccumulative-that is, they build up in progressively greater
concentrations as they are passed up the food chain. Top-line predators are particularly at risk, and their plight has been taken up by the new Ocean Wildlife campaign. Striped dolphins in the western North Pacific, for example, have concentrations of PCBs and DDT more than 10 million times higher than that of the water they live in.
Coastal Habitat Destruction: Pushed by Population
The medical waste that washed up on U.S. beaches in the summer of 1988 alerted many Americans to the dangers of ocean pollution.Photo: © Mark Sherman/Photo Network
The fate of the ocean is inextricably entwined with that of the coast. “The coasts,” says Beth Milleman of the Washington, D.C.-based Coast Alliance, “have been described as underwater rainforests because of the incredible diversity of life they contain, and there’s a lot of truth to that.”
Many ocean species rely on coastal habitats for breeding, feeding and shelter: one-third of the world’s marine fish species are found on coral reefs, the most productive coastal ecosystems of all, and it has been estimated that the total number of species of all kinds in reef systems could number a million. Other coastal habitats, such as mangroves and sea grasses, are also vital breeding, feeding and nursery areas for fish and shellfish species, home to a variety of wildlife species, and important protection and shelter against storms and coastal erosion. Ninety percent of the current world fisheries harvest comes from within 200 miles of the coast, and most of that within a strip of just five miles from the coast.
But the coastal zone is also home to the majority of the world’s population. As much as 66 percent of the world’s population lives within 40 miles of the shore, and coastal populations are growing faster than the global population as a whole. In the U.S. between 1960 and 1990, the population in coastal counties grew by 41 million, an increase of 43 percent. Between 1983 and 1991, 90 percent of all building activity in Australia took place within the coastal zone.
As a result of such growth in population and development, among other factors, coastal environments are coming under increasing pressure. It is estimated, for example, that, worldwide, as much as 10 percent of the world’s coral reefs have been degraded beyond recovery, and that another 30 percent is likely to decline within the next 15 or so years. Seventy-five percent of mangrove forests in the Philippines, and 40 percent in Ecuador, have been cut down to make way for aquaculture ponds. Around the world, seagrasses are being stifled by turbidity in the water as a result of nutrient pollution.
By interrupting the flow of freshwater from rivers, the construction of dams has impacted coastal regions and destroyed the habitats of many fish species worldwide: they are considered, for example, to be one of the primary causes in the extinction of at least 106 major populations of salmon and steelhead on the west coast.
Introduced Species: the Havoc of Exotic Migration
Although still an obscure problem, the constant introduction of exotic species to marine environments where they do not naturally occur is, says Dr. James Carlton, professor of marine science at Williams College-Mystic Seaport, Connecticut, playing “ecological roulette with the ocean. There is no way of knowing where and when the next invasion will occur, or what the consequences will be. But we do know that every time we introduce a species, we run the risk of radically transforming marine ecosystems, with tremendous ecological, economic and social consequences.”
The principal method by which exotic species are introduced into marine environments is through the intake and discharge of ballast water. When ships take on ballast at their point of departure, they also take on board thousands of microscopic organisms, including the planktonic life stages of larger plants and animals. As the ballast is emptied at the port of call, these passengers are discharged as well.
“We reckon that, at any time, there are 3,000 species in motion in ballast water,” says Carlton, “and that, somewhere in the world, one introduced species is taking hold every day.”
One dramatic example is the Atlantic comb jelly, a U.S. east coast native, introduced by ballast water into the Black and Azov Seas in the early 1980s. By 1988, it had become the dominant species in the Black Sea, leading to collapses in fish stocks and an estimated $250 million of lost fisheries revenue. Introduced species have also transformed marine ecosystems in the U.S.: there are at least 250 exotic organisms in San Francisco Bay alone, including the Asian clam, which is now found at densities of 3,000 per square foot.
The International Maritime Organization (IMO) is looking at ways to regulate ballast water discharge, and researchers in Australia and the United States are finding ways to tackle the problem by using heat to kill organisms in ballast water, or developing filters to trap the organisms when the ballast is discharged or taken on board. The island nation of Bonaire prohibits the dumping of ballast water in its coastal waters. But it is, admits Carlton, like “pushing a peanut uphill,” and in the meantime, more catastrophic species introductions seem certain to occur.
This 50-year-old American tank is part of the coastal debris in Saipan, Micronesia.Photo: © Paul Chesley Photographers/Aspen
Ozone Depletion: Climate Change and Global Warming
Finally, all these separate threats need to be placed in the context of overall global change, with an altered climate and increased ultraviolet radiation as a result of ozone depletion two prime examples.
According to a review by the Intergovernmental Panel on Climate Change (IPCC), a grouping of some 300 scientists from around the world, climate change “has the potential to significantly affect biological diversity in ocean and coastal areas. It could cause changes in the population sizes and distributions of species, alter the species composition and geographical extent of habitats and ecosystems, and increase the rate of species extinctions.”
These changes could come about, says the IPCC, through any combination of sea-level rise, increases in sea-surface temperature, increases in storms and other extreme events, and increased precipitation leading to greater run-off of pollutant-and-nutrient-rich soil and water into coastal areas. For example, rising sea-levels may swamp coastal habitats, and higher sea surface temperatures have already been implicated in some coral diseases and in nurturing some harmful algal blooms.
In addition, there is growing evidence that increased levels of UV-B radiation as a result of ozone depletion may be harming marine species, particularly those in the upper layers of the sea. Numerous studies have shown, for example, that increased UV-B can cause death, decreased reproductive capacity, reduced survival and impaired larval development in some of the plankton species that form the basis of the marine food chain.
The Healing Process
Given the size and extent of the ocean, and the complexity and variety of the issues it faces, addressing threats to the marine environment generally requires a multi-faceted approach. Because of the global nature of human activities that impact the ocean, many environmentalists concentrate their efforts on seeking to have those activities regulated or, if necessary, banned by international conventions.
Unfortunately, observes Clifton Curtis, political advisor to Greenpeace International, “There remains a tendency on the part of
international agreements to put the ocean in a box and say, ‘OK, we’ve done rainforests, now let’s address oceans.’ But ‘ocean issues’ cover such a wide range-fisheries, oil and gas, minerals, to name a few-that you can’t just fence them off that neatly.”
Not all ocean pollution is as obvious as this outflow pipe; industry has found subtler ways to manage its ocean dumping.Photo: H. Abernathy/H. Armstrong Roberts
That said, Curtis does see progress in the willingness of some countries to begin addressing those issues. Specifically, he cites the recent United Nations Convention on Straddling Fish Stocks and Highly Migratory Fish Stocks, developed to deal with the thorny issue of fisheries whose targets straddle or migrate between countries’ national waters and the high seas; the entry into force of the UN Law of the Sea, which covers a huge array of subjects, from navigation rights to fisheries to seabed mining; the interest of established agreements, such as the Convention on Biological Diversity and the Commission on Sustainable Development, in supporting ocean conservation; and the development, under the leadership of the United Nations Environment Program (UNEP), of a broad-based Global Program of Action for the Protection of the Marine Environment from Land-Based Activities.
Unfortunately, Curtis admits, it is often one thing for countries to adopt strict-sounding rules and regulations, and quite another to show the political will to enforce them. “For example, when it became clear that the Soviet Union had been dumping large amounts of radioactive material in the Kara and Barents Sea, in direct violation of the London Convention, very little was done. Certainly, no punitive measures were taken” (see sidebar).
Even when there is some element of political will on the part of a number of the signatories to a convention, it is not always enough. Fifteen years after the International Whaling Commission voted for an indefinite global moratorium on commercial whaling, for example, the IWC remains powerless to prevent Japan and Norway from killing hundreds of whales a year under the guise of “scientific research.”
Even getting to the stage where strong international commitments to protect the ocean are put down on paper has been, thanks to inertia from governments and pressure from industry, far from simple.
In 1995, for example, representatives of nations from around the world gathered in Washington, D.C., and agreed to negotiate a treaty that would severely curtail production and emissions of persistent organic pollutants. Initially, says Boyce Thorne-Miller, the plan had been to work toward eliminating the tens of thousands of such pollutants in existence; it was finally agreed, however, to concentrate on only 12. And while these are all important contaminants-including PCBs, DDT and dioxins-many of them, Thorne-Miller says, “are no longer made in Western Europe or the United States, so it’s not such a great hardship for the chemical industry to give them up. I overheard a member of one national delegation checking with an industry representative: ‘This list OK with you guys?’”
In another case, the MARPOL Convention on pollution from ships recently began attempting to address the issue of pollution as a result of nitrous and sulfurous compounds in ships’ fuel. But, says Sally Lentz, executive director of Ocean Advocates, “As a result of pressure from countries such as Mexico, which produces a lot of fuel with high sulfur content, we’re probably looking at an agreement that, instead of reducing the levels of sulfur in ships’ fuel, will set a cap that is higher than the levels that are actually commonly found right now.”
“To be honest,” sighs Mike Sutton, director of the Endangered Seas Campaign for WWF International, “I’ve become so disappointed with the political process that I’ve begun moving away from the political scene altogether. I tend to doubt that the political process is going to get us where we need to be. The inevitable compromise between conservation and exploitation almost invariably tends to leave us in a position which does not provide the protection the environment needs.”
None of which is to say that international conventions and agreements are without merit. Sutton agrees that “they need to get ratified and implemented.” Boyce Thorne-Miller sees them very much as “a tool that we can use to bring pressure on governments and industry.” Sally Lentz points out that, without the pressure from international agreements to set a timeline to phase out a particular technology or chemical, for example, such changes are unlikely to happen.
But, not least because of the laborious nature of bringing an agreement to fruition and the considerable weaknesses and loopholes that even the best agreements almost invariably contain, environmentalists are increasingly looking at other means to bring about change.
The WWF Endangered Seas Campaign, for example, has begun focusing more on the market-and, specifically, working with food giant Unilever to establish a Marine Stewardship Council, setting up a global, industry-wide mechanism for identifying and labeling sustainably-caught fish. In India, the National Fishworkers’ Forum is seeking to establish the first-ever international association of small-scale, inshore fishers, to draw global attention to the threat to their livelihood from giant offshore fishing fleets and the destructive environmental and social effects of shrimp aquaculture.
“I’ve never seen anything quite like” the burgeoning opposition to shrimp aquaculture, says Greenpeace’s international oceans campaign coordinator, Matthew Gianni. “It’s a real grass-roots movement, the thrust of which is trying to persuade American consumers—who, according to our research, eat more than 50 percent of the world’s farmed shrimp-that ‘all you can eat’ offers from Red Lobster or whatever really aren’t such good deals, at least not from the point of view of the environment or of inshore fishers in places like India, Bangladesh, Thailand and Ecuador.”
The outlook is bleak for this gray seal, trapped in a discarded fishing net. Similar debris kills 30,000 northern fur seals every year.Photo: Robin W. Baird/Earth Views
Indeed, for many, that kind of effort-making consumers and citizens aware of the way in which their actions impact on ocean and coastal ecosystems, sometimes thousands of miles away-is the most important exercise of all.
As Sylvia Earle observes, maybe what we need is to develop an “ocean ethic”-a recognition that the ocean, far from being a “great matrix that man cannot sully and cannot appreciably despoil,” an endless provider of resources or a bottomless sink for wastes, is as finite, and as vulnerable to human impacts, as any other environment. And the decisions that we all make-to build one more house near the coast, to drive a car when we could walk or take public transport, to eat one more plateful of shrimp-can all combine to the ocean’s detriment.
“There are many unknowns,” Earle admits, “but one thing is certain: we have the power to undermine the healthy functioning of the sea that supports us and all of the rest of life on Earth, but no sure way to heal the harm. For ages, the sea has taken care of us. For ourselves and all who follow, the time has clearly come for us to take care of the sea.”
KIERAN MULVANEY is a freelance writer, based in Washington, DC. He edits a monthly newsletter, Ocean Update, and is presently working on a book for the Independent World Commission on the Oceans.